3FE poor compression after head gasket job (1 Viewer)

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Hey guys, hoping to get some insight on this project im working on -

After doing a headgasket job on this 92 Land Cruiser I have, im discovering 0 compression on cylinder 1 and 35 on cylinder 4. The truck ran fine besides overheating before. When resurfacing the head at a shop they mentioned is was pretty warped from overheating..

Well during the process of putting in new valve seals from my gasket kit, I wire wheeled the valves since they were nasty. Now it seems my valves are leaking terribly. Has anyone else had experience with this? Whats the trick with getting valves to properly seal?

Or by chance am I missing something when installing the rocker arm assembly? Seems like all of the valves have little to no clearance. I didnt check the valve clearance before



After I cleaned the first few I remembered a previous miata project that I had the heck of a time getting the valves to seal after cleaning them and attempting to do a lapping job but took forever to seal. Ended up buying all new valves..

20200822_170338.jpg
 
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With due respect, I believe you have answered your own questions. Sounds like you need a new head and valves. Get a FSM so that you have a guide as to how to DIY properly; you will have better results. Best of luck.
 

Godwin

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With due respect, I believe you have answered your own questions. Sounds like you need a new head and valves. Get a FSM so that you have a guide as to how to DIY properly; you will have better results. Best of luck.

Doubtful the OP needs a new head but a proper valve regrind.

Pull the head and have the machine shop rework the valves and valve seats.
 
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With due respect, I believe you have answered your own questions. Sounds like you need a new head and valves. Get a FSM so that you have a guide as to how to DIY properly; you will have better results. Best of luck.
I was following the FSM and honestly during this part it wasn't much help.
 
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There's a post here in my rebuild/diagnosis/moral support thread that might be of use once you have the head off, and are inspecting the valves:
3FE Head Gasket

Stick with it, reach out if you need anything. This forum is the best I've seen in terms of support and "here's what I did that worked".
 
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I was following the FSM and honestly during this part it wasn't much help.

Make sure it's not the 60-series FSM, I made that mistake myself.
@jonheld has a digital incarnation of the FJ80 FSM, that I recommend.

Not that valves will be that different, but still. Specs can differ and I totally didn't gap my plugs to .031 before finding out there was a different FSM for our rigs. ;)
 
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Hey guys, hoping to get some insight on this project im working on -

After doing a headgasket job on this 92 Land Cruiser I have, im discovering 0 compression on cylinder 1 and 35 on cylinder 4. The truck ran fine besides overheating before. When resurfacing the head at a shop they mentioned is was pretty warped from overheating..

Well during the process of putting in new valve seals from my gasket kit, I wire wheeled the valves since they were nasty. Now it seems my valves are leaking terribly. Has anyone else had experience with this? Whats the trick with getting valves to properly seal?

Or by chance am I missing something when installing the rocker arm assembly? Seems like all of the valves have little to no clearance. I didnt check the valve clearance before



After I cleaned the first few I remembered a previous miata project that I had the heck of a time getting the valves to seal after cleaning them and attempting to do a lapping job but took forever to seal. Ended up buying all new valves..

View attachment 2413152
Can't be too careful. even if you wire wheel the valves which really shouldn't have an impact. Did you put the valves in the wrong order? sounds like there may be a open gap between those two cylinders. I've done lots of cylinder heads in my time and only had one fail. Check to make sure that the lifter is not pressing on top of the valve stem when the Piston is at the top dead center
 
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Seems like all of the valves have little to no clearance.

If the head was milled, all the valve clearances have changed since the head is closer to the block (and pushrods). You need to fully adjust the valves (with clearance) before attempting a compression test. Doing it cold is fine, but after it's running, then re-check the valves when fully hot.
 
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Seems like all of the valves have little to no clearance.

If the head was milled, all the valve clearances have changed since the head is closer to the block (and pushrods). You need to fully adjust the valves (with clearance) before attempting a compression test. Doing it cold is fine, but after it's running, then re-check the valves when fully hot.

I think your right on the money! Makes sense, thanks! You guys rock
 
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If you had the head milled, why would you NOT have the valves ground, guides checked, and new seals installed at the shop?

What you are describing is an improperly adjusted valve train.

You need to back off ALL rocker arms, then systematically adjust them to the cold specs on each and every cylinder, in order until they are all done. I hope you didn't jack the assembly by not loosening all the clearances before installing the rocker arm assembly.

Hopefully you installed each valve in the hole it came out of or you're pissing away a bunch of time and money. It will run for a while, although not great, since the valves are not matched to their seats.
 
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If you had the head milled, why would you NOT have the valves ground, guides checked, and new seals installed at the shop?

What you are describing is an improperly adjusted valve train.

You need to back off ALL rocker arms, then systematically adjust them to the cold specs on each and every cylinder, in order until they are all done. I hope you didn't jack the assembly by not loosening all the clearances before installing the rocker arm assembly.

Hopefully you installed each valve in the hole it came out of or you're pissing away a bunch of time and money. It will run for a while, although not great, since the valves are not matched to their seats.
That is exactly what I did 😬. Hopefully no damage happened, ill be finding out soon. Everything did go back in its original spot but I did not take into account the valve clearance would have changed after resurfacing the head. Havent worked on gear driven motors before. Thanks for the insight guys, exactly what I was hoping for when reaching out
 
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That is exactly what I did 😬. Hopefully no damage happened, ill be finding out soon. Everything did go back in its original spot but I did not take into account the valve clearance would have changed after resurfacing the head. Havent worked on gear driven motors before. Thanks for the insight guys, exactly what I was hoping for when reaching out
Do have an FSM to follow for adjusting the valves? (rocker arms)
 
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Doubtful the OP needs a new head but a proper valve regrind.

Pull the head and have the machine shop rework the valves and valve seats.

Also OP remember if you have a machine shop grind the seats to have them check the spring seat pressure. Some of the more lazy shops will just take care of the seats and not check pressure and shim as needed to bring it up to stock(which could also be down from heat/age).
 
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Also OP remember if you have a machine shop grind the seats to have them check the spring seat pressure. Some of the more lazy shops will just take care of the seats and not check pressure and shim as needed to bring it up to stock(which could also be down from heat/age).
Great info, thanks!
 

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